DJC wrote:

Also look on your council website for planning applications nearby. Most
council use very similar systems which usually include a large scale map
with makers for properties where there have been applications. You will
be able to view all the plans, justifications and objections online, so
not only get an idea of what is doable but what hoops the planners set.

Most councils only let you view the planning permission documents
though, not the building control documents.